The influence of bottom heat source on natural convective heat transfer characteristics in a two-dimensional square cavity fully filled with a homogeneous porous medium is numerically studied by the lattice Boltzmann method. In this physical model, the upper wall of porous cavity is set to be a cold heat source, and the bottom wall is designed as a local hot heat source. Both the left wall and the right wall are set to be adibatic. Specifically, the effects of both the position and size of bottom heat source on the properties of natural convective heat transfer are analyzed. The numerical results show that the position and size of bottom heat source have great influences on the characteristics of natural convective heat transfer, and there also exist the best position (a=4/16) and optimal size (b=0.75) of the bottom heat source for the maximal convective heat transfer intensity (N umax≈10.35) and heat exchange capacity (Qmax≈5.69).%运用格子Boltzmann方法研究了底部局部加热多孔介质方腔的自然对流传热.方腔的上壁面为低温热源,下壁面为局部高温热源,左右壁面为绝热条件.重点分析了高温热源位置a及尺寸b对多孔介质方腔自然对流传热性能的影响,提出了平均Nusselt数N u和位置a及尺寸b的拟合关系式.研究结果表明:高温热源位置及尺寸对多孔介质方腔内自然对流传热性质的影响很大,且存在最佳高温热源位置(a=4/16)和尺寸(b=0.75),以达到最强的对流换热强度(N umax≈10.35)和最大的对流换热量(Qmax≈5.69).
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